| Abstract: |
WC-based composite materials are widely used to fabricate wear-resistant coatings. Generally, thermal spray processes are the major approaches to fabricate WC-based composite coatings. But extremely high working temperature frequently results in phase transformation and inner crack of the thermal sprayed coating, degrading the coating performance. Cold spray as an alternative method exhibits great potentials to produce such wear-resistance coatings. However, the adhesive strength of cold sprayed WC-Co coatings is always low due to the lack of metal binder phase. Moreover, for the same reason, the working parameters for producing WC-Co coatings are very strict, significantly increasing the cost. In order to solve these problems, in this work, various percentage (ranging from 10wt.% to 50wt.%) of Ni powder as additional metal binder was mixed with the WC-12Co or WC-17Co powders to produce WC-Co-Ni composite coatings. The results indicated that WC-Co-Ni composite coating can be fabricated at low working parameters with the driving gas pressure and temperature of 2.8 MPa and 350, respectively. The cost was much lower than that for producing WC-Co coatings. Meanwhile, the original hard WC phase was found to almost completely retained in the composite coating without any mass loss. Mechanical and bonding strength tests indicated that cold sprayed WC-Co-Ni coatings possessed very high hardness and adhesive strength. Finally, all the coatings had excellent wear-resistance capability, particularly for the coating with lower Ni content.
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